In recent years, various technologies for displaying a three-dimensional image are proposed. As the above-mentioned technology, the three-dimensional image display technology, for example, using a liquid crystal shutter of an active shutter type and display devices such as a liquid crystal display device etc. of a time sharing type is known (for example, refer to Japanese Laid Open Patent Applications (1) to (3)).
Japanese Laid Open Patent Applications No. H10-191399 (1)
Japanese Laid Open Patent Applications No. 2000-275575 (2)
Japanese Laid Open Patent Applications No. 2007-110683 (3)
The liquid crystal display device displays the image for left eye and the image for right eye by turns. The liquid crystal shutter switches a liquid crystal panel for right eye and a liquid crystal panel for left eye to a transmissive state (ON) or a non-transmissive state (OFF) corresponding to the displayed images in the liquid crystal display device.
While the liquid crystal display device displays the image for left eye, the light emitted from the liquid crystal display device penetrates the liquid crystal panel for left eye, and is shut in the liquid crystal panel for right eye. Similarly, while the liquid crystal display device displays the image for right eye, the light emitted from the liquid crystal display device penetrates the liquid crystal panel for right eye, and is shut in the liquid crystal panel for left eye.
Thereby, the user wearing the liquid crystal shutter watches the image for right eye and the image for left eye by turns by right and left eyes, and the two-dimensional images displayed on the liquid crystal display can be perceived as a three-dimensional image. In this case, the liquid crystal shutter conducts a normal drive in synchronism with the image displayed by the liquid crystal display device based on the synchronization signal transmitted from the liquid crystal display device.
By the way, when the synchronization signal which a liquid crystal shutter receives stops according to a certain obstacle, if a sight line of the liquid crystal shutter user moves to other portion than the liquid crystal display, an interferential action arises between other light sources and the liquid crystal shutter. Therefore, the liquid crystal shutter user becomes unpleasant. Moreover, since high frequency driving of 120 Hz is performed in the normal drive and power consumption is large, the normal drive is unnecessary except viewing the three-dimensional image.
Moreover, since high-speed response is required for the liquid crystal shutter, it is desirable to use OCB (Optically Compensated Bend) liquid crystal for the liquid crystal shutter. However, in case of using the OCB liquid crystal, since the liquid crystal is in a splay alignment state in an initial stage, it is necessary to operate the liquid crystal after making the liquid crystal transit to a bend alignment state in the initial stage by applying a predetermined voltage. Moreover, if the predetermined voltage is not impressed to the OCB liquid crystal for a certain period, the OCB liquid crystal has character that the OCB liquid crystal reverse-transits from the bend alignment state to the splay alignment state. For this reason, when a power supply is turned off at the time of non-use of the liquid crystal shutter or the synchronization signal fails for a short-time, the OCB liquid crystal reverse-transits to the initial alignment state, that is, the splay alignment state. Accordingly, it is necessary to make the OCB liquid crystal transit to the bend alignment state from the splay alignment state again for continuous use, and further, there is a possibility that stability may be missing on that operation.